The epiphyte biomass of Posidonia oceanica (L.) Delile leaves is mainly related to the substrate leaf availability. It decreases with increasing depth and increases from winter to summer, following the ... [more ▼]

The epiphyte biomass of Posidonia oceanica (L.) Delile leaves is mainly related to the substrate leaf availability. It decreases with increasing depth and increases from winter to summer, following the leaf biomass changes. In Revellata Bay (Gulf of Calvi, Corsica), at shallow depth (10m in this study) where photophilous algae grow, the fixed epifauna biomass accounts for about one third of leaf epiphytes biomass. At deeper depths in the Revellata Bay (20 and 30m), where shade-tolerant algae are dominant among epiflora, epifauna may account for more than half the leaf epiphytes biomass. [less ▲]

in Cruz, J.; Raga, J. A.; Evans, P. G. H. (Eds.) European Research on Cetaceans - 13. Proceedings of the Thirteenth Annual Conference of the European Cetacean Society 5-8 April 1999. (1999)

Associations of tunas and dolphins in the wild are quite frequent events and the question arises how predators requiring similar diet in the same habitat share their environmental resources. As isotopic ... [more ▼]

Associations of tunas and dolphins in the wild are quite frequent events and the question arises how predators requiring similar diet in the same habitat share their environmental resources. As isotopic composition of an animal is related to that of its preys, stable isotopes (13C/12C and 15N/14N) analyses were performed in three predator species from the Northeast Atlantic: the striped dolphin, Stenella coeruleoalba, the common dolphin Delphinus delphis, and the albacore tuna, Thunnus alalunga, and compared to their previously described stomach content. Heavy metals (Cd, Zn, Cu and Fe) are mainly transferred through the diet and so, have been determined in the tissues of the animals. Albacore tunas muscles display higher 15N than in common and striped dolphins (mean: 11.4 0/00 vs. 10.3 0/00 and 10.4 0/00, respectively) which reflects its higher trophic level. Higher 13C are found in common (-18.4 0/00) and striped dolphin (-18.10/00) muscles than in albacore tuna (-19.3 0/00). Differences also appear in heavy metal contents, especially cadmium in muscles, lower in albacore tuna than in dolphins (0.37 and 0.1 ppm DW for striped and common dolphins vs.<0.07 ppm DW for albacore tuna) which probably reflects in dolphins a cadmium contamination through squid assimilation. These results suggest that, despite a close hunting association, the trophic position of these three predators is quite well distinct. [less ▲]

During 6 successive wintering periods, 727 common guillemots Uria aalge were recovered from Belgian beaches. One-third of the birds were already dead; the rest passed through rehabilitation centres where ... [more ▼]

During 6 successive wintering periods, 727 common guillemots Uria aalge were recovered from Belgian beaches. One-third of the birds were already dead; the rest passed through rehabilitation centres where they eventually died. All birds were monitored for general condition (body mass, fat reserves), eventual status of oiling and pathological changes (cachexia, acute hemorrhagic gastroenteropathy); 339 birds were sampled for trace metals (total and organic Hg, Cu, Zn, Fe, Cd) and PCB (polychlorinated biphenyl) analysis. Oiling is still a major cause of death for wintering pelagic seabirds: half of the birds showed signs of external or internal oiling, probably a still greater number of oiled birds never reach the shores. Although a low body mass can be considered a normal winter condition for wintering guillemots, pathology results showed that three-quarters of the studied animals were in a state of cachexia with emaciated pectoral muscle and lowered muscle lipid content. Elevated levels of Cu, Zn, Hg and PCBs were linked to the state of cachexia and may well represent an additional stress factor leading to the debilitation and death of part of the wintering guillemot population. [less ▲]

In Revellata Bay (Gulf of Calvi, Corsica, France), the sparid fish Sarpa salpa L. is the main macro-consumer of Posidonia oceanica (L.) DELILE leaf. Stomach contents were analysed and C-13/C-12 isotopic ratios were measured in fish muscle and potential food sources (algae, P. oceanica leaf and its epiphytes) to determine their relative contribution to the fish diet. S. salpa has an age-related mixed diet: juveniles are plankton feeders, young, sub-adults and adults are herbivorous, and, the older the individuals, the higher the relative contribution of P. oceanica to the diet. Our results and former studies of carbon stocks and fluxes in the P. oceanica bed of Revellata Bay have enabled an estimation of the general impact of S. salpa grazing on infralittoral communities: the studied species consumes 24 g C.m-2.a(-1) from P. oceanica leaf, 4.8 from epiphytes and 13 from epilithic algae. The fish net production and biomass turnover in that zone have been estimated to be 1.2 g C.m(-2).a(-1) and 1.5 a(-1), respectively. [less ▲]

A new, completely automated gas chromatography technique has been developed to separate the different gaseous compounds produced during underground coal gasification for their C-13/C-12 and D/H isotope ... [more ▼]

A new, completely automated gas chromatography technique has been developed to separate the different gaseous compounds produced during underground coal gasification for their C-13/C-12 and D/H isotope ratio measurements, ?he technique was designed for separation and collection of Hz, CO, CO2, H2O, H2S, CH4, and heavier hydrocarbons. These gaseous compounds are perfectly separated by the gas-phase chromatograph and quantitatively sent to seven combustion and collection lines. H-2, CO, CH4, and heavier hydrocarbons are quantitatively oxidized to CO2 and/or H2O. The isotopic analyses are performed by the sealed-tube method, The zinc method is used for reduction of both water and H2S to hydrogen for D/H analysis, Including all preparation steps, the reproducibility of isotope abundance values, for a quantity higher than or equal to 0.1 mt of individual components in a mixture (5 mt of gases being initially injected in the gas chromatograph), is +/-0.1 parts per thousand for delta(13)C(PDB) and +/-6 parts per thousand for delta(13)C(PDB) and +/-6 parts per thousand for delta(SMOW). [less ▲]